Does oxygen use during general anesthesia cause an artifact in magnetic resonance images?

Objectives: In this study our aim was to compare possible effects of two different oxygen concentrations (100% vs. 50%) on hyperintense signal abnormality (HSA) in pediatric patients undergoing cranial magnetic resonance imaging (MRI) under sevoflurane anesthesia. Materials and methods: Thirty pediatric patients undergoing cranial MRI were studied. Sevoflurane was used for induction and maintenance of anesthesia with an MR-compatible anesthesia machine. Patients, whose airway patency was maintained with laryngeal mask, were divided randomly in two groups. 100% oxygen and 50% oxygen/50% nitrous oxide was used for maintenance of anesthesia in Group I and II, respectively. FLAIR sequence images were analyzed by a radiologist who was unaware of the groups and were evaluated for HSA in 11 different brain regions in cerebrospinal fluid neighborhood. A three-point scale was used for evaluation. Results: HSA was seen in all study patients at least in one brain region. However, no significant difference was obtained between two groups in almost all brain regions (p>0.05). Conclusions: Use of oxygen in pediatric patients undergoing cranial MRI under sevoflurane anesthesia caused a low grade HSA. However, concentration of oxygen had no significant effect on the severity of HSA.